WASHINGTON, D.C. — Maine’s long fight to allow 100,000-pound trucks on its federal interstates scored a victory Tuesday in Washington, but faces more challenges as it works its way through Congress, according to members of Maine’s congressional delegation.

Republican Sen. Susan Collins, the ranking member of the Senate Transportation Appropriations Subcommittee, said in a press release that she has inserted a provision into a 2012 transportation funding bill to allow 100,000-pound trucks on Maine’s interstate highways permanently.

The funding bill faces votes by the full Senate Appropriations Committee on Wednesday and then the full Senate. To become law, a similar provision would have to be introduced into the House version of the budget bill, which so far has not happened. Democratic Rep. Mike Michaud said he was working on the issue through a separate bill he has sponsored.

Collins said Maine’s 80,000-pound truck weight limit puts the state at a disadvantage on many fronts.

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“Public safety, our economy, energy independence and the environment have always been among my top priorities in the Senate,” said Collins in a press release. “My provision to permanently change federal law would advance all of those goals by allowing the heaviest trucks to travel on our federal interstates in Maine rather than being forced to use secondary roads and downtown streets.”

Higher truck weights have been supported by Maine’s congressional delegation for years. Heavier trucks weighing a total of 100,000 pounds including freight were allowed on Maine’s highways during a one-year pilot project that ended in December 2010. Since then, the weight limit on highways such as I-95, I-295 and I-395 has been back down to 80,000 pounds, forcing heavier trucks onto secondary state roads and, in some cases, through downtowns.

Collins cited data from the Maine Department of Transportation that showed crashes involving trucks decreased by 72 during the pilot program, compared the average number of crashes over the previous five years.

The language inserted into the transportation spending bill by Collins also would allow a similar permanent change to truck weight limits in Vermont. At issue in Maine are 260 miles of federal interstates which are not part of the Maine Turnpike.

Republican Sen. Olympia Snowe applauded Collins’ success in securing truck weights language into the budget bill. Snowe also has been working on the issue through a measure called the Commercial Truck Safety Act, which she introduced in July in an effort to equalize truck weight limits at 100,000 pounds across the country through a three-year pilot program. The bill would also create a safety committee that would ultimately determine whether the provision would become permanent.

“The current treatment of truck weights on interstate highways is a glaring example of a bureaucratic regulation creating both safety hazards on secondary roads and tangible barriers to job growth at a time when the nation’s unemployment rate is stuck above 9 percent and Maine’s mill towns are struggling to thrive,” said Snowe in a press release. “As I have said before, it is critical our Congressional delegation approach this issue from every angle to achieve our ultimate goal: getting trucks back on the Interstate in Maine.”

Michaud, who also praised Collins for her work on the budget bill, also is working for higher truck weights through his own bill, which he said in a press release has 54 bipartisan sponsors, including a Republican senator who has introduced the bill in the Senate.

“This is a positive step forward for an issue that Maine’s delegation has been pushing to address for years,” said Michaud in the release. “I’m hopeful the bill it’s attached to advances quickly and congressional leaders don’t oppose its inclusion. I’ll do whatever I can to support this moving forward.”

The heavier truck weight limits have broad support in Maine ranging from law enforcement agencies to members of the Legislature to freight industry officials, but are opposed by some safety groups who say 100,000-pound trucks should not be allowed anywhere because of dangers associated with the greater weight. Advocates argue that the restrictions in Maine and Vermont put those states at a disadvantage compared to New Hampshire, Massachusetts, New York and neighboring Canadian provinces where 100,000-pound trucks are allowed.